Main active components of Jiawei Gegen Qinlian decoction protects against ulcerative colitis under different dietary environments in a gut microbiota-dependent manner.

As an effective drug against acute enteritis diarrhea, Gegen Qinlian decoction (GQD) has a history of 2000 years. However, the potential molecular mechanism through which GQD could protect intestinal barrier from ulcerative colitis (UC) still remains undefined. As an important part of the homeostasis of the colon, gut microbiota is closely related to the dynamic evolution of the surrounding environment and the adjustment of dietary structure. At present, the effectiveness and mechanism of Jiawei Gegen Qinlian decoction against UC in different dietary environments are not clear. Here, the main active components of Jiawei Gegen Qinlian Decoction (PBM), were selected to construct a reasonable and effective compound scheme. We adopted "5% dextran sulfate sodium (DSS)" and "high temperature and humidity + high sugar and high fat + alcohol + 5%DSS" to induce UC rat models in general environment and UC rat models in Lingnan area, respectively. Then, we examined the therapeutic effects of PBM (89.96 mg/kg and 179.92 mg/kg) on two kinds of UC rats. The role of gut microbiota in the anti-UC effect of PBM was identified by intestinal flora consumption and fecal microbiota transplantation (FMT) experiments. Subsequently, we monitored the alterations of gut microbiota and fecal metabolism in the rat colon by 16Sr DNA technique and targeted metabonomics, respectively. The colon inflammation of the PBM-treated and the FMT-treated rats both showed significant relief, as evidenced by a reduction in body weight loss, bloody stool, diarrhea, disease activity index (DAI) score, shortening of colon length as well as decreased colon histology damage. Interestingly enough, the depletion of intestinal flora took away the protective effect of PBM, confirming the importance of intestinal flora in the anti-UC effect of PBM. Then our findings suggested that PBM could not only regulate the gut microbiota by increasing Akkermansia and Romboutsia but also decrease Escherichia-Shigella. More importantly, PBM could increase the production of propionate and total short-chain fatty acids (SCFAs) in colitis rats, regulate medium and long chain fatty acids (M-LCFAs), maintain bile acids (BAs) homeostasis, and regulate amino acids (AAs) metabolism. The transformation of intestinal environment might be related to the upregulation of anti-inflammation, anti-oxidation and tight junction protein expression in colonic mucosa. In summary, PBM showed potential for anti-UC activity through gut microbiota dependence and was expected to be a complementary and alternative medicine herb therapy.

Li Q ，Cui Y ，Xu B ，Wang Y ，Lv F ，Li Z ，Li H ，Chen X ，Peng X ，Chen Y ，Wu E ，Qu D ，Jian Y ，Si H ... -  《-》

Gegen Qinlian decoction ameliorates TNBS-induced ulcerative colitis by regulating Th2/Th1 and Tregs/Th17 cells balance, inhibiting NLRP3 inflammasome activation and reshaping gut microbiota.

Chinese herbal medicine Gegen Qinlian Decoction (GQD) has been clinically shown to be an effective treatment of ulcerative colitis (UC) in China. However, the underlying mechanism of GQD's anti-ulcerative colitis properties and its effect on gut microbiota still deserve further exploration. This study observed the regulatory effects of GQD on Th2/Th1 and Tregs/Th17 cells balance, the NOD-like receptor family pyrin domain containing 3 (NLRP3) infammasome and gut microbiota in TNBS-induced UC in BALB/c mice. 61 main chemical compounds in the GQD were determined by UPLC-Q-TOF/MS. The UC BALB/c model was established by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and GQD was orally administered at low and high dosages of 2.96 and 11.83 g/kg/day, respectively. The anti-inflammatory effects of GQD for ulcerative colitis were evaluated by survival rate, body weight, disease activity index (DAI) score, colonic weight and index, spleen index, hematoxylin-eosin (HE) staining and histopathological scores. Flow cytometry was used to detect the percentage of CD4, Th1, Th2, Th17 and Tregs cells. The levels of Th1-/Th2-/Th17-/Tregs-related inflammatory cytokines and additional proinflammatory cytokines (IL-1β, IL-18) were detected by CBA, ELISA, and RT-PCR. The expressions of GATA3, T-bet, NLRP3, Caspase-1, IL-Iβ, Occludin and Zonula occludens-1 (ZO-1) on colon tissues were detected by Western blot and RT-PCR. Transcriptome sequencing was performed using colon tissue and 16S rRNA gene sequencing was performed on intestinal contents. Fecal microbiota transplantation (FMT) was employed to assess the contribution of intestinal microbiota and its correlation with CD4 T cells and the NLRP3 inflammasome. GQD increased the survival rate of TNBS-induced UC in BALB/c mice, and significantly improved their body weight, DAI score, colonic weight and index, spleen index, and histological characteristics. The intestinal barrier dysfunction was repaired after GQD administration through promoting the expression of tight junction proteins (Occludin and ZO-1). GQD restored the balance of Th2/Th1 and Tregs/Th17 cells immune response of colitis mice, primarily inhibiting the increase in Th2/Th1 ratio and their transcription factor production (GATA3 and T-bet). Morever, GQD changed the secretion of Th1-/Th2-/Th17-/Tregs-related cytokines (IL-2, IL-12, IL-5, IL-13, IL-6, IL-10, and IL-17A) and reduced the expressions of IL-1β, IL-18. Transcriptome results suggested that GQD could also remodel the immune inflammatory response of colitis by inhibiting NOD-like receptor signaling pathway, and Western blot, immunohistochemistry and RT-PCR further revealed that GQD exerted anti-inflammatory effects by inhibiting the NLRP3 inflammasome, such as down-regulating the expression of NLRP3, Caspase-1 and IL-1β. More interestingly, GQD regulated gut microbiota dysbiosis, suppressed the overgrowth of conditional pathogenic gut bacteria like Helicobacter, Proteobacteria, and Mucispirillum, while the probiotic gut microbiota, such as Lactobacillus, Muribaculaceae, Ruminiclostridium_6, Akkermansia, and Ruminococcaceae_unclassified were increased. We further confirmed that GQD-treated gut microbiota was sufficient to relieve TNBS-induced colitis by FMT, involving the modulation of Th2/Th1 and Tregs/Th17 balance, inhibition of NLRP3 inflammasome activation, and enhancement of colonic barrier function. GQD might alleviate TNBS-induced UC via regulating Th2/Th1 and Tregs/Th17 cells Balance, inhibiting NLRP3 inflammasome and reshaping gut microbiota, which may provide a novel strategy for patients with colitis.

Hu Y ，Tang J ，Xie Y ，Xu W ，Zhu W ，Xia L ，Fang J ，Yu D ，Liu J ，Zheng Z ，Zhou Q ，Shou Q ，Zhang W ... -  《-》

Gegen Qinlian decoction activates AhR/IL-22 to repair intestinal barrier by modulating gut microbiota-related tryptophan metabolism in ulcerative colitis mice.

Gegen Qinlian decoction (GQD) is a traditional Chinese medicine derived from Treatise on febrile diseases and is clinically used for the treatment of acute ulcerative colitis (UC). However, the potential mechanism of GQD treatment for UC remains elusive. In this study, we aimed to explore the involvement of gut microbiota-related tryptophan metabolism in mediating protective effects of GQD against intestinal barrier damage. Mice with colitis were treated with 3% dextran sulfate sodium (DSS) for 6 days. The therapeutic effects of GQD in UC mice were examined based on body weight, disease activity index (DAI), organ index, length and pathological changes in the colon. The distribution of fluorescein isothiocyanate dextran (FITC-dextran) in the intestinal tract was observed using small animal imaging, while concentration of FITC-dextran in serum was detected using a fluorescein microplate analyser. Bacterial infiltration in colon tissues was observed by fluorescence in situ hybridisation (FISH), and the bacterial load in mesenteric lymph nodes (MLNs) was further examined through bacterial culture. Subsequently, colonic goblet cells were detected using Alcian blue staining. The tight junctions of the colonic epithelium were observed using transmission electron microscopy, and the expression of tight junction proteins was detected by immunofluorescence (IF) and western blot. In addition, flow cytometry was used to analyse the proportion of interleukin-22-positive (IL-22+) ILC3 cells in lamina propria lymphocytes, and the content of IL-22 in colon homogenates was determined using an ELISA kit. In addition, targeted tryptophan metabolomics was used to detect the concentration of indole derivatives produced by tryptophan metabolism in faeces, and 16S rDNA was used to investigate the composition and abundance of gut microbiota-related tryptophan metabolism. Administration of GQD significantly alleviated the pathological symptoms, including weight loss, increased DAI score, changes in organ index, colon shortening, and colon pathological injury in UC mice. In addition, GQD reduced the diffusion of FITC-dextran in the intestinal tract, the content of FITC-dextran in serum, and bacterial infiltration in MLNs and colon tissues. Additionally, GQD significantly increased the number of colonic goblet cells, repaired the structure of epithelial tight junctions and increased the expression of tight junction proteins. Furthermore, GQD significantly increased the proportion of IL-22+ ILC3 in the lamina propria, the expression of CYP1A1 protein in colon tissue, and the level of IL-22 in colon homogenates. However, the above protective effects of GQD were inhibited by co-administration of GQD and aryl hydrocarbon receptor (AhR) antagonist. Additionally, GQD restored the content of indole derivatives generated by tryptophan metabolism, regulated the diversity of the gut microbiota, and significantly increased the abundance of genes related to tryptophan metabolism. Our results confirmed that GQD repaired the damaged intestinal barrier in UC mice by regulating gut microbiota-related tryptophan metabolism and restoring the generation of indole derivatives to activate AhR-mediated IL-22 production.

Wang X ，Huang S ，Zhang M ，Su Y ，Pan Z ，Liang J ，Xie X ，Wang Q ，Chen J ，Zhou L ，Luo X ... -  《-》

Modified Gegen Qinlian Decoction modulated the gut microbiome and bile acid metabolism and restored the function of goblet cells in a mouse model of ulcerative colitis.

Modified Gegen Qinlian Decoction (MGQD) has been shown to effectively relieve ulcerative colitis (UC) without a known pharmacological mechanism. In this study, the anti-colitis efficaciousness of MGQD and its underlying mechanisms in UC were evaluated. Mice with colitis were administered MGQD for 7 days. Following the evaluation of clinical symptoms, gut microbiota in the feces of UC mice was examined using 16S rRNA sequencing and bile acids (BAs) were examined using LC/MS. Gut microbiota consumption and fecal microbiota transplantation (FMT) were used to explore the involvement of gut microbiota in the anti-UC action of MGQD. MGQD relieved colitis as shown by weight loss protection, a lower disease activity index (DAI), restoration of intestinal length reduction, and lower histopathologic scores. MGQD also restored crypt stem cell proliferation and function of colonic goblet cells, and promoted MUC2 protein secretion. Interestingly, investigations using gut bacterial depletion and FMT showed that MGQD attenuated colonic damage in a gut-dependent way. The modulation of the gut microbiota by MGQD might be attributed to a decrease in Odoribacter and an increase in norank_f_Muribaculaceae. In addition, MGQD modulated the metabolism of BAs while restoring the structure of the gut microbiota. MGQD significantly alleviated colitis in mice, which may be associated with the modulation of gut microbiota and BA metabolism and restoration of function of goblet cells. However, factors other than the gut microbiota may also be involved in the amelioration of UC by MGQD.

Huang J ，Zhang J ，Wang F ，Tang X ... -  《Frontiers in Immunology》

Ethanol extract of Centella asiatica alleviated dextran sulfate sodium-induced colitis: Restoration on mucosa barrier and gut microbiota homeostasis.

Ulcerative colitis (UC) is a relapsing inflammatory disease that still demands for effective remedies due to various adverse effects of the current principal treatments. Centella asiatica is a traditional medical herb with long application history in anti-inflammation. To explore the anti-inflammatory effect and possible mechanism of C. asiatica ethanol extract (CA) in a murine colitis model induced by dextran sulfate sodium (DSS). CA was analyzed by high performance liquid chromatograph (HPLC). The colitis model was induced by free access to 3% DSS in distilled water for 7 days. CA (100, 200, and 400 mg/kg) and 5-aminosalicylic acid (5-ASA, 400 mg/kg) were administrated by gavage during the 7-day DSS challenge. At the end of experiment, mice were sacrificed and the brain, colon and cecum contents were harvested for analysis. Colitis was evaluated by disease activity index (DAI), colon length and colon lesion macroscopic score with hematoxylin-eosin staining. Myeloperoxidase (MPO) activity in colon and 5-hydroxytryptamine (5-HT) in brain were determined by ELISA. Tight junction protein expressions (ZO-1, E-Cadherin, Claudin-1) and c-Kit in colon were assessed by western blot and immunohistochemistry, respectively. Microbiota of cecum content was analyzed by 16S rRNA sequencing. Data showed that with recovery on the colon length and histological structure, CA prominently decreased DAI and macroscopic score for lesion in the suffering mice. CA relieved the colitis by suppressing inflammatory cell infiltration with decreased MPO activity in the colon, and up-regulated the expression of tight junction protein (ZO-1, E-cadherin) to enhance the permeability of intestinal mucosa. Moreover, CA restored intestinal motility by promoting c-Kit expression in the colon and 5-HT in the brain. Moreover, CA was able to reshape the gut microbiota in the suffering mice. It increased the α-diversity and shifted the community by depleting the colitis-associated genera, Helicobacter, Jeotgalicoccus and Staphylococcus, with impact on several metabolism signaling pathways, which possibly contributes to the renovation on the impaired intestinal mucosal barrier. CA displayed the anti-inflammatory activity against the DSS-induced colitis, which would possibly rely on the restoration on mucosa barrier and gut microbiota homeostasis, highlights a promising application of C. asiatica in the clinical treatment of UC.

Li H ，Chen X ，Liu J ，Chen M ，Huang M ，Huang G ，Chen X ，Du Q ，Su J ，Lin R ... -  《-》